Until now, we've always edited a single object only. To add additional ones, like a ground floor or rocks to the scene, we can use subtools. We'll always use subtools, when it makes sense to split objects to be able to edit them separately. For instance, when modeling different outfits for a hero character, you would like them to be appended as subtools, so you can switch them on and off. A good example would be a knight with his armor appended as a subtool.
Once we have several subtools appended, we'll use the Transpose tool to put them into place. Let's see how this works: